Table of Contents

Filed pursuant to Rule 424(b)(2)

Registration No. 333-155221

PROSPECTUS SUPPLEMENT

To Prospectus dated December 4, 2008

$25,000,000

Common Stock

We have entered into an equity distribution agreement with Piper Jaffray & Co. relating to shares of our common stock, par value $0.001 per share, offered by this prospectus supplement and the accompanying prospectus. In accordance with the terms of the equity distribution agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $25.0 million from time to time through Piper Jaffray & Co., our sales agent. Sales of the shares, if any, will be made by means of ordinary brokers’ transactions on the NASDAQ Global Market at market prices. Additionally, under the terms of the equity distribution agreement, we may also sell shares of our common stock through Piper Jaffray, as sales agent, on the NASDAQ Global Market or otherwise, at negotiated prices or at prices related to the prevailing market price. We will pay Piper Jaffray & Co. a commission equal to 3% of the gross sales price per share of shares sold through it as sales agent under the equity distribution agreement. Piper Jaffray & Co., as sales agent, will use its commercially reasonable efforts to sell shares of common stock on our behalf on a daily basis or as otherwise agreed upon by us and Piper Jaffray & Co.

Under the terms of the equity distribution agreement, we may also sell shares of our common stock to Piper Jaffray & Co. for its own account at a price agreed upon at the time of sale. If we sell shares to Piper Jaffray & Co. as principal, we will enter into a separate terms agreement with Piper Jaffray & Co. and will describe this agreement in a separate prospectus supplement or pricing supplement.

Investing in our common stock involves risks.  See “Risk Factors” beginning on page S-4 of this prospectus supplement for a discussion of the material risks you should consider before making an investment in our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete.  Any representation to the contrary is a criminal offense.

Piper Jaffray

The date of this prospectus supplement is September 18, 2009

Table of Contents

TABLE OF CONTENTS

We provide information to you about this offering of shares of our common stock in this prospectus supplement, which describes the specific details regarding this offering, and in the accompanying prospectus, which provides general information, some of which may not apply to this offering. Generally, when we refer to this “prospectus,” we are referring to both documents combined.

You should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus.  We have not, and Piper Jaffray & Co. has not, authorized anyone to provide you with information different from that contained or incorporated by reference in this prospectus supplement or the

S-i

Table of Contents

accompanying prospectus.  These documents do not constitute an offer to sell or solicitation of an offer to buy these shares of common stock in any circumstance under which the offer or solicitation is unlawful.  The information contained in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein and therein are accurate only as of their respective dates, regardless of the time of delivery of this prospectus supplement or the sale of our common stock.  If information in this prospectus supplement, or information incorporated by reference in this prospectus supplement and the accompanying prospectus that is of a more recent date than the accompanying prospectus, is inconsistent with the accompanying prospectus, this prospectus supplement, or the information incorporated by reference in this prospectus supplement and the accompanying prospectus, will apply and will supersede that information in the accompanying prospectus.

References in this prospectus supplement to “Array,” “we,” “our” or “us” refer to Array BioPharma Inc.  Our trademarks include the Array BioPharma logo and the terms “Array BioPharma,” “Array BioPharma The Discovery Research Company,” “Turning Genomics Into Breakthrough Drugs,” “Optimer,” and “Array Discovery Platform.” Other trademarks and trade names appearing in this prospectus supplement and the accompanying prospectus are the property of the respective holders of such trademarks and trade names.

S-ii

Table of Contents

PROSPECTUS SUPPLEMENT SUMMARY

This summary does not contain all of the information that you should consider before investing in our common stock. You should read this entire prospectus supplement and the accompanying prospectus carefully, including “Risk factors,” and the financial statements and other information incorporated by reference in this prospectus supplement and the accompanying prospectus, before making an investment in our common stock.

Our Business

We are a biopharmaceutical company focused on the discovery, development and commercialization of targeted small molecule drugs to treat patients afflicted with cancer, inflammatory and metabolic diseases.  Our proprietary drug development pipeline includes clinical candidates that are designed to regulate therapeutically important target proteins and are aimed at significant unmet medical needs.  In addition, leading pharmaceutical and biotechnology companies collaborate with Array to discover and develop drug candidates across a broad range of therapeutic areas. We currently have seven wholly-owned programs in our development pipeline:

1.               ARRY-403, a glucokinase activator for Type 2 diabetes

2.               ARRY-162, a MEK inhibitor for cancer

3.               ARRY-380, an ErbB-2 inhibitor for breast cancer

4.               ARRY-520, a KSP inhibitor for acute myeloid leukemia and multiple myeloma

5.               ARRY-614, a p38/Tie 2 dual inhibitor for myelodysplastic syndrome

6.               ARRY-543, an ErbB family (ErbB-2 / EGFR) inhibitor for solid tumors

7.               ARRY-797, a p38 inhibitor for subacute pain and cancer supportive care indications

We also have a portfolio of proprietary and partnered drug discovery programs that we believe will generate one to two Investigational New Drug, or IND, applications during fiscal 2010.  Our drug discovery efforts have also generated additional early-stage drug candidates that we may choose to out-license through research partnerships prior to filing an IND application.  Our drug discovery programs include an inhibitor that targets the kinase Chk-1 for the treatment of cancer and an inhibitor that targets a family of tyrosine kinase, or Trk, receptors for the treatment of pain.  Our Chk-1 inhibitor is a first-in-class, selective, oral drug candidate and in preclinical studies has shown prolonged inhibition of the Chk-1 target.  Our Trk family inhibitor is a first-in-class, selective, oral drug candidate targeting Trk A, B, and C.

Our Strategy

We are building a fully integrated, commercial-stage biopharmaceutical company that invents, develops and markets safe and effective small molecule drugs to treat patients afflicted with cancer, inflammatory and metabolic diseases. We intend to accomplish this through the following strategies:

·                  Inventing targeted small molecule drugs that are either first-in-class or second generation drugs that demonstrate a competitive advantage over drugs currently on the market or in clinical development;

·                  Partnering select drugs after establishing proof-of-concept data for co-development and commercialization, while retaining the right to commercialize and/or co-promote any resulting drugs in the U.S.;

·                  Partnering select early-stage programs for continued research and development in exchange for research funding, plus significant milestone payments and royalties;

S-1

Table of Contents

·                  Leveraging our clinical development organization to provide timely, robust proof-of-concept data; and

·                  In the longer term, conducting later-stage development and seeking marketing approval for important new drugs across multiple therapeutic areas and building commercial capabilities to position our drugs to maximize their overall value.  As our first drug nears approval, we plan to build a U.S.-based, therapeutically-focused sales force to commercialize and/or co-promote our drugs.

We have a large number of research and development programs, and therefore partnering these programs with collaborators that will provide funding, development, manufacturing and commercial resources is central to our strategy over the next several years.  These partnerships may include co-development or co-commercialization and either may be worldwide or limited to certain geographic areas.  We plan to advance our most promising development assets internally through clinical proof-of-concept before partnering them, which we believe will maximize their value.  However, we are also identifying certain programs to partner earlier during discovery or preclinical development with the goal of optimizing the potential return for Array on these programs.

Our Corporate Information

Founded in 1998, we are headquartered in Boulder, Colorado and employ over 355 full-time employees, including 227 scientists, of whom 116 have PhD’s or MD’s. We became a public company in November 2000, and our stock is listed on the NASDAQ Global Market under the symbol “ARRY.”  The mailing address and telephone number of our principal executive offices are 3200 Walnut Street, Boulder, Colorado 80301, (303) 381-6600. Our website address is http://www.arraybiopharma.com. Information contained in, or accessible through, our website does not constitute a part of this prospectus supplement or the accompanying prospectus.

S-2

Table of Contents

THE OFFERING

S-3

Table of Contents

RISK FACTORS

Investment in our common stock involves a high degree of risk. In addition to the other information included or incorporated by reference in this prospectus supplement and the accompanying prospectus, you should carefully consider the risks described below and in the section entitled “Risk Factors” in our Annual Report on Form 10-K for our most recent fiscal year filed with the Securities and Exchange Commission, and in other reports we file with the Securities and Exchange Commission that are incorporated by reference herein, before making an investment decision.  The risks and uncertainties described therein and below could adversely affect our business, operating results and financial condition, as well as cause the value of our common stock to decline.  You may lose all or part of your investment as a result.  You should also refer to the other information contained in this prospectus supplement and the accompanying prospectus, or incorporated by reference, including our financial statements and the notes to those statements, and the information set forth under the caption “Special Note Regarding Forward-Looking Statements.”  The risks described below and contained in our Annual Report on Form 10-K and in our other periodic reports are not the only ones that we face.  Additional risks not presently known to us or that we currently deem immaterial may also affect our business operations.

Additional Risks Related to Our Stock and the Offering

There are a substantial number of shares of our common stock eligible for future sale in the public market, and the sale of these shares could cause the market price of our common stock to fall.

There were 48,135,776 shares of our common stock outstanding as of September 16, 2009. We also had outstanding as of September 16, 2009 warrants that become exercisable on January 31, 2010 to purchase an aggregate of (i) 6,000,000 shares of our common stock at an exercise price of $3.65 per share and (ii) 6,000,000 shares of our common stock at an exercise price of $4.19 per share that were issued to Deerfield Private Design Fund, L.P., Deerfield Private Design International Fund, L.P., Deerfield Partners, L.P. and Deerfield International Limited (who we refer to collectively as the Deerfield Funds) in accordance with Facility Agreements dated April 28, 2008 and May 15, 2009 (which we refer to, as each such agreement has been amended, as the Facility Agreements). We may also be required to issue additional shares under the warrants in connection with a redemption of the warrants or upon certain failure payments that may be satisfied in shares of common stock following certain major transactions, events of default and upon the occurrence of certain events specified in the warrants.  On August 31, 2009, we filed a registration statement registering the resale of up to an aggregate of 14,000,000 shares of our common stock that may be issuable under these warrants. In addition, subject to certain restrictions, we may issue up to an aggregate of 9,622,220 shares of common stock that are registered under the Securities Act of 1933, as amended, under the Facility Agreements with the Deerfield Funds to satisfy payments of interest and principal thereunder.

In addition to our outstanding warrants, as of September 16, 2009, there were (i) options to purchase 9,212,565 shares of our common stock outstanding under our Amended and Restated Stock Option and Incentive Plan at a weighted-average exercise price of $7.52, (ii) 5,107,750 additional shares of common stock available for issuance under our Amended and Restated Stock Option and Incentive Plan, and (iii) 1,023,885 shares of common stock remaining issuable under our Employee Stock Purchase Plan (of which shares 600,000 are subject to approval by our stockholders at our 2009 Annual Meeting of stockholders).

The shares issuable under our Amended and Restated Stock Option and Incentive Plan and our Employee Stock Purchase Plan, and to Deerfield in repayment of interest and principal under the Facility Agreements, will be available for immediate resale in the public market.  Once the warrants are exercisable, the shares issuable under the warrants will be available for immediate resale in the public market following the effectiveness of the registration statement we have filed with respect to the resale of such shares. The market price of our common stock could decline as a result of such resales due to the increased number of shares available for sale in the market.

New investors in our common stock could experience immediate and substantial dilution.

The offering price of our common stock could be substantially higher than what the net tangible book value per share of our common stock is at the time of any offering.  As a result, purchasers of our common stock in this offering could incur immediate and substantial dilution.  For example, assuming the full $25.0 million in shares of our common stock that are subject to the equity distribution agreement are sold at a price to the public of $2.79 per

S-4

Table of Contents

share, the last reported sales price of our common stock on September 16, 2009, the purchasers would experience immediate dilution of approximately $3.66 per share.  Those purchasers could experience additional dilution upon the exercise of outstanding stock options having an exercise price less than the per share offering price to the public in this offering. See “Dilution” for a more detailed discussion of the dilution new investors will incur in this offering.

Management may invest or spend the proceeds of this offering in ways with which you may not agree and in ways that may not yield a return to our stockholders.

We will retain broad discretion over the use of proceeds from this offering. We expect to use the net proceeds from this offering to fund our research and development efforts and for general corporate purposes, including working capital. We may also use the net proceeds from this offering to make payments of interest or principal under the Facility Agreements with the Deerfield Funds.  A number of variables will influence our actual use of the proceeds from this offering, and our actual uses of the proceeds of this offering may vary substantially from our currently planned uses. Management could choose to spend the net proceeds from this offering in ways in which stockholders may not deem desirable, or in ways that do not improve our operating results or result in a significant return or any return at all for our stockholders.

S-5

Table of Contents

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement and the accompanying prospectus contain and incorporate by reference certain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements that are not descriptions of historical facts are forward-looking statements, based on management’s estimates, assumptions and projections that are subject to risks and uncertainties. These statements can generally be identified by the use of forward-looking terminology such as “believes,” “expects,” “intends,” “may,” “will,” “should,” or “anticipates” or similar terminology and include, but are not limited to, statements concerning our future drug development plans and projected timelines for the initiation and completion of preclinical and clinical trials; the potential for the results of ongoing preclinical or clinical trials to support regulatory approval or the marketing success of drug candidates; our plans with respect to the timing and scope of the expansion of our clinical and commercialization capabilities; other statements regarding our future product development and regulatory strategies, including with respect to specific indications; the ability of third-party contract manufacturing parties to support our drug development activities; any statements regarding our future financial performance or results of operations, our projections regarding the level of cash we expect to use in operations or the sufficiency of our capital resources to fund our operating requirements; and any other statements which are other than statements of historical fact.

These statements reflect our current views about future events and are subject to significant risks and uncertainties, including those discussed below and those described more fully in other reports filed by Array with the Securities and Exchange Commission, or the SEC. Because these statements reflect our current expectations concerning future events, our actual results could differ materially from those anticipated in these forward-looking statements. The factors that could cause actual results to differ from our expectations include, but are not limited to, our ability to continue to fund and successfully progress internal research and development efforts and to create effective, commercially viable drugs; our ability to out-license our proprietary candidates on favorable terms; the ability of our collaborators and of Array to meet objectives tied to milestones and royalties; our ability to effectively and timely conduct clinical trials in light of increasing costs and difficulties in locating appropriate trial sites and in enrolling patients who meet the criteria for certain clinical trials; our ability to achieve and maintain profitability and to maintain sufficient cash resources; the extent to which the pharmaceutical and biotechnology industries are willing to in-license drug candidates for their product pipelines and to collaborate with and fund third parties on their drug discovery activities; risks associated with our dependence on our collaborators for the clinical development and commercialization of our out-licensed drug candidates; our ability to attract and retain experienced scientists, and management; and the risk factors set forth above under the caption “Risk Factors.” The forward-looking statements contained herein represent our judgment as of the date of this prospectus supplement. Except as required by law, we undertake no duty to update any forward-looking statements to reflect the occurrence of events or circumstances that arise after the date of this prospectus supplement or the filing of the accompanying prospectus or documents incorporated by reference herein and therein that include forward-looking statements.

S-6

Table of Contents

USE OF PROCEEDS

We intend to use the net proceeds from the sale of shares of our common stock in this offering to make payments of interest under our outstanding credit facilities with the Deerfield Funds. Simple interest on the $120 million in principal amount outstanding under the Facility Agreements is currently accruing at the rate of 7.5% per annum and is payable monthly. The interest rate is subject to adjustment, from 8.5% to 14.5% per annum, based on the outstanding balance of our cash, cash equivalents and marketable securities. Outstanding principal and any unpaid accrued interest under our credit facilities are due April 29, 2014.

In addition, we may use the net proceeds of this offering to fund our research and development efforts, including clinical trials for our proprietary candidates, and for general corporate purposes, including working capital. The amounts and timing of these expenditures will depend on a number of factors, such as the timing and progress of our research and development efforts, technological advances and the competitive environment for our drug candidates. As of the date of this prospectus supplement, we have not allocated any portion of the net proceeds from this offering for any particular uses other than payments of interest under the Facility Agreements. Accordingly, we will retain broad discretion over the use of any additional proceeds not used to repay such interest. Pending these uses, we intend to invest the net proceeds in investment-grade, interest-bearing securities.

PRICE RANGE OF OUR COMMON STOCK

Our common stock has been quoted on the NASDAQ Global Market under the symbol “ARRY” since our initial public offering on November 17, 2000. The following table sets forth, for the periods indicated, the reported high and low sales prices per share of our common stock as reported by the NASDAQ Global Market:

As of September 16, 2009, the closing price of our common stock as reported by the NASDAQ Global Market was $2.79 per share and there were 72 holders of record of our common stock. This does not include the number of persons whose stock is in nominee or “street name” accounts through brokers.

S-7

Table of Contents

DIVIDEND POLICY

We have never declared or paid any cash dividends on our common stock. We currently intend to retain any future earnings to finance the growth and development of our business. Therefore, we do not anticipate that we will declare or pay any cash dividends on our common stock in the foreseeable future. Any future determination to pay cash dividends will be at the discretion of our Board of Directors and will depend on our financial condition, results of operations, capital requirements, restrictions under any existing indebtedness and other factors the Board of Directors deems relevant.

DILUTION

If you purchase shares of our common stock from us, your interest will be diluted to the extent of the difference between the public offering price per share you pay and the net tangible book value per share of our common stock immediately after this offering. Our net tangible book value as of June 30, 2009, was $(73.7) million, or $(1.53) per share of common stock. Net tangible book value per share is calculated by subtracting our total liabilities from our total tangible assets, which is total assets less intangible assets of $0, and dividing this amount by the number of shares of common stock outstanding as of June 30, 2009. Assuming we sold the entire aggregate amount of $25.0 million provided for in the equity distribution agreement at an assumed price to the public of $2.79 per share, the last reported sale price of our common stock on September 16, 2009, and after deducting the estimated commissions and offering expenses payable by us, our adjusted net tangible book value as of June 30, 2009 would have been $(49.6) million, or $(0.87) per share of common stock. This would represent an immediate increase in the net tangible book value of $0.66 per share to our existing stockholders and an immediate and substantial dilution in the net tangible book value of $3.66 per share of common stock to new investors. The following table illustrates this calculation on a per share basis:

The information in the table above is provided for illustrative purposes and assumes that all of our common stock offered hereby in the aggregate amount of $25.0 million is sold at a price of $2.79 per share, the last reported sale price of our common stock on September 16, 2009. The shares, if any, sold pursuant to the equity distribution agreement will be sold from time to time at various prices that will depend largely on the market price of our common stock at the time of sale. An increase, or decrease, of $1.00 per share in the price at which the shares are sold from the assumed offering price of $2.79 per share shown in the table above, assuming all of our common stock in the aggregate amount of $25.0 million is sold at that price, would increase (or decrease) our adjusted net tangible book value per share after the offering by $(0.04) and $0.07 per share, respectively, and the dilution in net tangible book value per share new investors in this offering by $1.04 and $(1.07) per share, respectively, after deducting the estimated commissions of Piper Jaffray & Co. and estimated aggregate offering expenses payable by us.

The information in the foregoing table does not take into account further dilution to new investors that could occur upon the exercise of outstanding options having a per share exercise price less than the price per share at which new investors purchase the shares offered hereby. As of June 30, 2009, there were 48,125,776 shares of common stock outstanding, which does not include:

·                  9,263,265 shares issuable upon exercise of options outstanding at a weighted average exercise price of $7.06 per share;

·                  5,110,750 shares of common stock available for future issuance under our Amended and Restated Stock Option and Incentive Plan;

·                  423,885 shares of common stock available for future issuance under our Employee Stock Purchase Plan;

·                  6,000,000 shares of common stock issuable upon exercise of outstanding warrants at an exercise price of $3.65 per share; and

·                  up to 9,622,220 shares of common stock we may issue, subject to certain restrictions, at varying prices in satisfaction of our obligations to make interest and principal payments under our credit facilities with the Deerfield Funds.

S-8

Table of Contents

PLAN OF DISTRIBUTION

We have entered into an equity distribution agreement with Piper Jaffray & Co. (“Piper Jaffray”). Subject to the terms and conditions of the equity distribution agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $25.0 million from time to time through Piper Jaffray. Sales of the shares, if any, will be made by means of ordinary brokers’ transactions on the NASDAQ Global Market at market prices. Additionally, under the terms of the equity distribution agreement, we may also sell shares of our common stock through Piper Jaffray, as sales agent, on the NASDAQ Global Market or otherwise, at negotiated prices or at prices related to the prevailing market price. As sales agent, Piper Jaffray will not engage in any transactions that stabilize our common stock.

Piper Jaffray, as sales agent, will use its commercially reasonable efforts to sell shares of common stock on our behalf on a daily basis or as otherwise agreed upon by us and Piper Jaffray. We will designate the maximum amount of shares of common stock to be sold through Piper Jaffray on a daily basis or otherwise as we and Piper Jaffray agree. We may instruct Piper Jaffray not to sell shares of common stock if the sales cannot be effected at or above the price designated by us in any such instruction. We or Piper Jaffray may suspend the offering of shares of common stock by notifying the other.

We will pay Piper Jaffray a commission equal to 3% of the gross sales price per share of shares sold through it as sales agent in connection with the equity distribution agreement. The remaining sales proceeds, after deducting any expenses payable by us and any transaction fees imposed by any governmental or self-regulatory organization in connection with the sales, will equal our net proceeds for the sale of the shares. All expenses of the offering will be paid by us. We estimate that the expenses of the offering payable by us, excluding discounts and commissions, will be approximately $125,000. We have also agreed to reimburse Piper Jaffray for certain of its expenses.

Settlement for sales of common stock will occur on the third business day following the date on which any sales were made in return for payment of the net proceeds to us. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

Under the terms of the equity distribution agreement, we also may sell shares to Piper Jaffray as principal for its own account at a price agreed upon at the time of sale. If we sell shares to Piper Jaffray as principal, we will enter into a separate terms agreement with Piper Jaffray and we will describe this agreement in a separate prospectus supplement or pricing supplement. Piper Jaffray may offer the shares of common stock sold to it as principal from time to time through public or private transactions at market prices prevailing at the time of sale, at fixed prices, at negotiated prices, at various prices determined at the time of sale or at prices related to prevailing market prices.

In connection with the sale of common stock on our behalf, Piper Jaffray may be deemed to be an “underwriter” within the meaning of the Securities Act of 1933, as amended, and the compensation paid to Piper Jaffray may be deemed to be underwriting commissions or discounts. We have agreed to indemnify Piper Jaffray against certain liabilities, including liabilities under the Securities Act, or to contribute to payments that Piper Jaffray may be required to make. Piper Jaffray may engage in transactions with, or perform other services for, us in the ordinary course of business.

Our shares are quoted on the NASDAQ Global Market under the symbol “ARRY.”

In compliance with the guidelines of the Financial Industry Regulatory Authority, Inc. (“FINRA”), the maximum discount or commission to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate offering price of the shares offered pursuant to this prospectus supplement.

If Piper Jaffray or we have reason to believe that our common stock is no longer an “actively-traded security” as defined under Rule 101(c)(1) of Regulation M under the Securities Exchange Act of 1934, as amended, that party will promptly notify the other, and sales of common stock under the equity distribution agreement and any terms agreement may be suspended until that or other exemptive provisions have been satisfied in the judgment of Piper Jaffray and us.  Moreover, in connection with any future sales of common stock made under the equity distribution agreement or terms agreement, Regulation M may require that Piper Jaffray observe certain restrictions with respect to its trading of our common stock. Such restrictions could negatively impact the liquidity in our common stock.

S-9

Table of Contents

The offering of common stock pursuant to the equity distribution agreement will terminate upon the earlier of (i) the sale of all shares of common stock subject to the equity distribution agreement or (ii) the termination of the equity distribution agreement by either Piper Jaffray or us.

LEGAL MATTERS

The validity of the common stock offered by this prospectus supplement and the accompanying prospectus will be passed upon for us by Hogan & Hartson L.L.P., Boulder, Colorado. Certain legal matters in connection with the offering of the common stock will be passed upon for Piper Jaffray & Co. by Latham & Watkins LLP, Costa Mesa, California.

EXPERTS

The financial statements of Array BioPharma Inc. as of June 30, 2009 and 2008 and for each of the years in the three-year period ended June 30, 2009, and management’s assessment of the effectiveness of internal control over financial reporting as of June 30, 2009, have been incorporated by reference herein and in the registration statement in reliance on the reports of KPMG LLP, independent registered public accounting firm, incorporated by reference herein and upon the authority of said firm as experts in accounting and auditing.

MATERIAL CHANGES

Following the end of fiscal 2009, we identified a deficiency in our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) of the Exchange Act) that resulted in a failure to furnish the information contained in our quarterly financial results press release under Item 2.02 of Form 8-K for the six quarters ended June 30, 2009. Each of the press releases was disseminated to the public through widely circulated newswire services and were timely submitted to NASDAQ MarketWatch. In addition, the associated quarterly reports on Form 10-Q were filed with the SEC the same day or the next day as the applicable press releases, and the associated annual reports on Form 10-K were filed within one week of the applicable press releases. We also held conference calls, the date, time and access information for which were communicated to the public by widely disseminated press releases, that were open to the public via telephone or webcast. To remediate the deficiency, we have provided additional training to certain investor relations and accounting personnel. We have also implemented new review and tracking procedures and approval requirements in connection with the issuance of press releases to provide additional assurance that information announced in press releases that require a Form 8-K filing are identified and the information is filed or furnished on a timely basis. Management has concluded that these steps have remediated the deficiency and that our disclosure controls and procedures are effective as of the date of this prospectus supplement.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement under the Securities Act that registers the distribution of the securities offered under this prospectus. The registration statement, including the attached exhibits and schedules and the information incorporated by reference, contains important information about our company and the securities. The rules and regulations of the SEC allow us to omit from this prospectus certain information included in the registration statement. In addition, we file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy this information and the registration statement at the SEC’s Public Reference Room located at 100 F Street, N.E., Washington D.C. 20549. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the public reference room.

In addition, any information we file with the SEC, including the registration statement and the documents incorporated by reference into this prospectus, and the exhibits thereto, is also available on the SEC’s website at http://www.sec.gov. We also maintain a website at http://www.arraybiopharma.com, which provides additional information about our company and through which you can also access our SEC filings. Information contained in,

S-10

Table of Contents

or accessible through, our website does not constitute a part of this prospectus supplement or the accompanying prospectus.

IMPORTANT INFORMATION INCORPORATED BY REFERENCE

The SEC allows us to incorporate by reference the information that we file with the SEC, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus. These documents may include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as Proxy Statements. Any documents that we subsequently file with the SEC will automatically update and replace the information previously filed with the SEC. Thus, for example, in the case of a conflict or inconsistency between information set forth in this prospectus and information incorporated by reference into this prospectus, you should rely on the information contained in the document that was filed later.

This prospectus incorporates by reference the documents listed below that we have previously filed (under File No. 001-1633) with the SEC and any additional documents that we may file with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act between the date of this prospectus and the termination of the offering of the securities. These documents contain important information about us.

1.     Our Annual Report on Form 10-K for the year ended June 30, 2009 filed with the SEC on August 18, 2009;

2.     Our Current Reports on Form 8-K filed with the SEC on July 8, 2009, July 15, 2009, August 6, 2009, August 10, 2009, August 17, 2009 and September 4, 2009 (except to the extent such information was furnished to and not filed with the SEC); and

3.    The description of our common stock contained in our Registration Statement on Form 8-A filed with the SEC on November 16, 2000, including any amendment or report filed for the purpose of updating such descriptions.

You can obtain a copy of any or all of these documents, including any exhibits thereto, at no cost, by visiting the Investor Relations section of our web site at http://www.arraybiopharma.com or by requesting them in writing or by telephone at the following address:

Array BioPharma Inc.
3200 Walnut Street
Boulder, Colorado 80301
(303) 381-6600
Attention: Investor Relations

Statements contained in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein referring to the contents of any contract or other document are not necessarily complete. Where such contract or other document is listed as an exhibit to the Registration Statement on Form S-3, of which this prospectus supplement and the accompanying prospectus form a part, or any document incorporated by reference therein, each such statement is qualified by the provisions in such exhibit, to which reference is hereby made.

Information contained in, or accessible through, our website does not constitute a part of this prospectus supplement or the accompanying prospectus.

S-11

Table of Contents

PROSPECTUS

ARRAY BIOPHARMA INC.

UP TO $150,000,000 OF OUR
COMMON STOCK
PREFERRED STOCK
DEPOSITARY SHARES
WARRANTS

We may offer from time to time up to $150,000,000 in total of any combination of the securities described in this prospectus.  Any preferred stock we sell may be sold as either shares of preferred stock or represented by depositary shares.  We may offer the common stock, preferred stock, depositary shares and warrants (collectively, the “securities”) separately or together, in separate series, in amounts, at prices and on terms to be set forth in one or more supplements to this prospectus.

Each time we plan to issue securities, we will circulate a prospectus supplement, which will contain a description of the securities being offered and information about the specific terms, the public offering price of the securities and the net proceeds we expect to receive from such sale, and may add, update or change information contained in this prospectus.  You should read this prospectus and the prospectus supplements carefully before you invest.

The securities may be sold directly by us to investors, through agents designated from time to time or to or through underwriters or dealers.  We will set forth the names of any underwriters or agents in an accompanying prospectus supplement. For additional information on the methods of sale, you should refer to the section entitled “Plan of Distribution.”

Our common stock is listed on the Nasdaq Global Market and traded under the symbol “ARRY.”  On November 5, 2008, the last reported sale price for our common stock was $4.07 per share.

An investment in our securities involves a high degree of risk. You should carefully consider the “Risk Factors” contained in any supplements to this prospectus and in our most recent annual report on Form 10-K and in our other filings made with the Securities and Exchange Commission, which are incorporated by reference in this prospectus.

This prospectus may not be used to offer or sell securities unless accompanied by a prospectus supplement.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is December 4, 2008

Table of Contents

TABLE OF CONTENTS

i

Table of Contents

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the SEC using a “shelf” registration process. Under this shelf process, we may from time to time offer up to $150,000,000 in any combination of the securities described in this prospectus.  We may sell these securities either individually or as units consisting of one or more of such securities, each at prices and on terms to be determined at the time of sale. The common stock, preferred stock, depositary shares and warrants are collectively referred to in this prospectus as the “securities.” The securities offered pursuant to this prospectus may be one or more series of issuances, and the total offering price of the securities will not exceed $150,000,000.

This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement, or information incorporated by reference in this prospectus or any prospectus supplement that is of a more recent date, may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with the additional information described below under the heading “Where You Can Find More Information.”  These documents do not contain an offer to sell or solicitation of an offer to buy the securities in any circumstance in which the offer or solicitation is unlawful.  This prospectus may not be used to consummate a sale of securities unless it is accompanied by a prospectus supplement.

You should rely only on the information provided in the registration statement of which the prospectus is a part, this prospectus, any prospectus supplement and any documents incorporated by reference in this prospectus or any prospectus supplement. We have not authorized anyone to provide you with different information. The information in this prospectus or any prospectus supplement is accurate only as of the date of the document on the front of the document, and any information we have incorporated by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any sale of a security.

References in this prospectus to “Array,” “the company,” “we,” “our” or “us” refer to Array BioPharma Inc.  Our trademarks include the Array BioPharma logo and the terms “ARRAY BIOPHARMA,” “ARRAY BIOPHARMA THE DISCOVERY RESEARCH COMPANY,” “TURNING GENOMICS INTO BREAKTHROUGH DRUGS,” “OPTIMER,” and “ARRAY DISCOVERY PLATFORM.”  Other trademarks and trade names appearing in this prospectus are the property of the holders of such trademarks and trade names.

ii

Table of Contents

SUMMARY

Our Business

We are a biopharmaceutical company focused on the discovery, development and commercialization of targeted small molecule drugs aimed at large market opportunities.  Our proprietary drug development pipeline includes clinical candidates that are designed to treat patients afflicted with cancer, inflammatory diseases and pain.  In addition, leading pharmaceutical and biotechnology companies collaborate with us to discover and develop drug candidates across a broad range of therapeutic areas.

The mailing address and telephone number of our principal executive offices are 3200 Walnut Street, Boulder, Colorado 80301, (303) 381-6600.

Securities We May Offer

We may offer any of the following securities with a total value of up to $150,000,000 from time to time under this prospectus at prices and on terms to be determined by market conditions at the time of the offering:

·                  common stock;

·                   preferred stock, in one or more series;

·                   depositary shares;

·                   warrants to purchase shares of common stock, shares of preferred stock or depositary shares; or

·                   any combination of the foregoing securities.

We refer to our common stock, preferred stock, depositary shares and warrants collectively in this prospectus as the “securities.” This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, including, to the extent applicable:

·                  designation or classification;

·                  aggregate offering price;

·                  rates and times of payment of dividends, if any;

·                  redemption, conversion or sinking fund terms, if any;

·                  voting or other rights, if any;

·                  conversion prices, if any; and

·                  important federal income tax considerations.

Common Stock. We may offer shares of our common stock. Our common stock currently is listed on the Nasdaq Global Market under the symbol “ARRY.”  Shares of common stock that may be offered in this offering will, when issued and paid for, be fully paid and non-assessable.

Preferred Stock. We may offer shares of our preferred stock, in one or more series. Our board of directors will determine the rights, preferences, privileges and restrictions of the preferred stock, including any dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of

1

Table of Contents

shares constituting any series or the designation of any series. Convertible preferred stock will be convertible into shares of our common stock. Conversion may be mandatory or at your option and would be at prescribed conversion rates. Shares of preferred stock that may be offered in this offering will, when issued and paid for, be fully paid and non-assessable.  The terms of the preferred stock we may offer under this prospectus and any prospectus supplement will be set forth in a certificate of designation relating to that series and will be incorporated by reference into the registration statement of which this prospectus is a part.  We urge you to read the complete certificate of designation containing the terms of the applicable series of preferred stock, as well as the applicable prospectus supplement related to such series.

Depositary Shares. We may from time to time issue receipts for depositary shares representing fractional shares of our preferred stock. Any depositary shares that we sell under this prospectus will be evidenced by depositary receipts issued under a deposit agreement between us and a depositary with whom we deposit the shares of the applicable series of preferred stock that underlie the depositary shares that are sold. Subject to the terms of the deposit agreement, each holder of a depositary share will be entitled, in proportion to the applicable fraction of a share of the preferred stock underlying the depositary share, to all of the rights, preferences and privileges, and be subject to the qualifications and restrictions, of the preferred stock underlying that depositary share. We will incorporate by reference into the registration statement of which this prospectus is a part the form of deposit agreement, including a form of depositary receipt, that describes the terms of any depositary shares that we are offering before the issuance of the related depositary shares. We urge you to read the prospectus supplements related to any depositary shares being offered, as well as the complete depositary agreement and depositary receipt that contains the terms of the depositary shares.

Warrants.  We may issue warrants for the purchase of shares of our common stock or preferred stock or depositary shares in one or more series. Warrants may be issued independently or together with the securities offered by any prospectus supplement and may be attached to or separate from such securities. Further terms of the warrants will be set forth in warrant certificates issued under warrant agreements between us and an agent for the warrant holders, which we will incorporate by reference into the registration statement of which this prospectus is a part, as well as in the applicable prospectus supplement relating to such warrants. We urge you to read the prospectus supplements related to the series of warrants being offered, as well as the complete warrant agreements and warrant certificates that contain the terms of the applicable series of warrants.

2

Table of Contents

RISK FACTORS

Investment in our securities involves risks.  Prior to making a decision about investing in our securities, you should consider carefully the risk factors, together with all of the other information contained or incorporated by reference in this prospectus and any prospectus supplement, including any additional specific risks described in the section entitled “RISK FACTORS” contained in any supplements to this prospectus and in our most recent annual report on Form 10-K and in our quarterly reports on Form 10-Q filed with the SEC, as well as any amendments thereto reflected in subsequent filings with the SEC, which are incorporated herein by reference in their entirety.  Each of these risk factors could adversely affect our business, operating results and financial condition, which may result in the loss of all or part of your investment.

SPECIAL NOTE REGARDING

FORWARD-LOOKING STATEMENTS

This prospectus contains and incorporates by reference certain forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995.  All statements that are not descriptions of historical facts are forward-looking statements, based on management’s estimates, assumptions and projections that are subject to risks and uncertainties.  These statements can generally be identified by the use of forward-looking terminology such as “believes,” “expects,” “intends,” “may,” “will,” “should,” or “anticipates” or similar terminology.

These statements involve significant risks and uncertainties, including those discussed below and those described more fully in other reports filed by Array with the SEC. Because these statements reflect our current expectations concerning future events, our actual results could differ materially from those anticipated in these forward-looking statements as a result of many factors. These factors include, but are not limited to, our ability to continue to fund and successfully progress internal research and development efforts and to create effective, commercially viable drugs; our ability to effectively and timely conduct clinical trials in light of increasing costs and difficulties in locating appropriate trial sites and in enrolling patients who meet the criteria for certain clinical trials; our ability to achieve and maintain profitability; the extent to which the pharmaceutical and biotechnology industries are willing to in-license drug candidates for their product pipelines and to collaborate with and fund third parties on their drug discovery activities; our ability to out-license our proprietary candidates on favorable terms; risks associated with our dependence on our collaborators for the clinical development and commercialization of our out-licensed drug candidates; the ability of our collaborators and of Array to meet objectives tied to milestones and royalties; our ability to attract and retain experienced scientists, and management; and the risk factors set forth under the caption “Risk Factors” in our most recent annual report on Form 10-K and our quarterly reports on Form 10-Q, and any amendments thereto we file with the SEC, and in any supplements to this prospectus. The forward-looking statements contained herein represent our judgment as of the date of this prospectus.  We undertake no duty or obligation to update any forward-looking statements to reflect the occurrence of events or circumstances after the date of such statements or of anticipated or unanticipated events that alter any assumptions underlying such statements.

USE OF PROCEEDS

Except as described in any prospectus supplement, we intend to use the net proceeds from the sale of our securities to fund our research and development efforts and for general corporate purposes, including working capital. We may also use a portion of the net proceeds to acquire or invest in businesses or technologies that are complementary to our business, although we have no present commitments or agreements to do so. Pending these uses, we intend to invest the net proceeds in investment-grade, interest-bearing securities.

DESCRIPTION OF CAPITAL STOCK

The following description of our capital stock and material provisions of our amended and restated certificate of incorporation and bylaws is only a summary.  The description is qualified in its entirety by the complete provisions of our amended and restated certificate of incorporation, which has been filed as an exhibit to the registration statement on Form S-1 (file no. 333-45922) filed with the SEC on September 15, 2000, and the amendment thereto filed as an exhibit to the current report on Form 8-K filed with the SEC on November 6, 2007 (File No. 001-16633), and our amended and restated bylaws, which have been filed as an exhibit to the current report on Form 8-K filed with the SEC on November 4, 2008 (File No. 001-16633).  Our amended and

3

Table of Contents

restated certificate of incorporation authorizes the issuance of up to 120,000,000 shares of common stock, par value $0.001 per share, and 10,000,000 shares of preferred stock, par value $0.001 per share. As of November 6, 2008, 47,587,792 shares of common stock were issued and outstanding and no shares of preferred stock were issued and outstanding.

Listing

Our common stock is listed on the Nasdaq Global Market and traded under the symbol “ARRY.”

Transfer Agent and Registrar

American Stock Transfer and Trust Company is our transfer agent and registrar.

Common Stock

Each holder of common stock is entitled to one vote for each share on all matters to be voted upon by the stockholders.  Holders of common stock are not entitled to cumulative voting rights with respect to the election of directors. Subject to preferences that may be applicable to any preferred stock outstanding at the time, holders of common stock are entitled to receive ratable dividends, if any, as may be declared from time to time by the board of directors out of funds legally available for that purpose.  In the event of our liquidation, dissolution or winding up, holders of common stock would be entitled to share ratably in all assets remaining after the payment of liabilities and liquidation preferences on any outstanding preferred stock.  Holders of common stock have no preemptive or conversion rights or other subscription rights and there are no redemption or sinking fund provisions applicable to the common stock.  All outstanding shares of common stock are, and shares of common stock offered by us in this offering, when issued and paid for, will be, fully paid and nonassessable.

Preferred Stock

Our board of directors is authorized, without stockholder approval, to issue up to an aggregate of 10,000,000 shares of preferred stock in one or more series. The board of directors can fix the rights, preferences, privileges and restrictions of the preferred stock, including dividend rights, dividend rates, conversion rights, voting rights, terms of redemption, redemption prices, liquidation preferences and the number of shares constituting any series of the designation of such series, without further vote or action by the stockholders.

We will fix the rights, preferences, privileges and restrictions of the preferred stock of each series in the certificate of designation relating to that series. We will incorporate by reference as an exhibit to the registration statement that includes this prospectus or as an exhibit to a current report on Form 8-K, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. We urge you to read the complete certificate of designation containing the terms of the applicable series of preferred stock, as well as the applicable prospectus supplement related to such series. The certificate of designation will include:

·                  the title and stated value; the number of shares we are offering;

·                  the liquidation preference per share;

·                  the purchase price;

·                  the dividend rate, period and payment date and method of calculation for dividends;

·                  whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

·                  the procedures for any auction and remarketing, if any;

4

Table of Contents

·                  the provisions for a sinking fund, if any;

·                  the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

·                  any listing of the preferred stock on any securities exchange or market;

·                  whether the preferred stock will be convertible into our common stock, and, if applicable, the conversion price, or how it will be calculated, and the conversion period;

·                  voting rights, if any, of the preferred stock;

·                  preemption rights, if any;

·                  restrictions on transfer, sale or other assignment, if any;

·                  whether interests in the preferred stock will be represented by depositary shares;

·                  a discussion of any material or special United States federal income tax considerations applicable to the preferred stock;

·                  the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

·                  any limitations on issuance of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

·                  any other specific terms, preferences, rights or limitations of, or restrictions on, the preferred stock.

If we issue shares of preferred stock under this prospectus, the shares will be fully paid and non-assessable and will not have, or be subject to, any preemptive or similar rights.

The General Corporation Law of the State of Delaware, the state of our incorporation, provides that the holders of preferred stock will have the right to vote separately as a class on any proposed fundamental change in the rights of the preferred stock. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

We may amend from time to time our amended and restated certificate of incorporation to increase the number of authorized shares of preferred stock. Any such amendment would require the approval of the holders of a majority of the voting power of the shares entitled to vote thereon.

Future issuances of preferred stock may have the effect of delaying or preventing a change in our control or make removal of our management more difficult. Additionally, the issuance of preferred stock could decrease the amount of earnings and assets available for distribution to the holders of the common stock or could adversely affect the rights and powers, including voting rights, of the holders of our common stock. The issuance of preferred stock could also cause the market price of our common stock to decline.

Registration Rights

Prior to our initial public offering and in connection with the sale and issuance of our Series A preferred stock in May 1998, and August 1998, our Series B preferred stock in November 1999, and our Series C preferred stock in August 2000, we entered into an agreement with the investors in such financings providing for registration rights with respect to the shares of common stock, including those issuable upon conversion of each series of preferred stock, held and subsequently acquired by these investors. Currently, 2.5 million shares of our common stock are

5

Table of Contents

entitled to registration rights pursuant to terms and conditions of this agreement. The registration rights under this agreement allow the holders of at least 30% of the shares of common stock held by such holders then outstanding to require us to register their shares under the Securities Act on up to two occasions, subject to limitations described in the agreement.  In addition, these holders can require us to include their shares in future registrations of our shares for our account or the account of another stockholder.  These holders may also require us to register their shares on up to two occasions in any calendar year on Form S-3.  These registration rights are subject to limitations and conditions, including the right of underwriters to limit the number of shares of common stock held by existing stockholders to be included in a registration.  The registration rights as to any holder will terminate when all securities held by the holder entitled to registration rights can be sold within a three-month period under Rule 144 of the Securities Act and when the number of shares held by the holder is less than 1% of our outstanding capital stock on an as converted to common stock basis.  In addition, we are generally required to bear all expenses of registration, including the reasonable fees of a single counsel acting on behalf of all selling stockholders, except underwriting discounts and selling commissions.

In connection with a Facility Agreement entered into as of April 29, 2008 between Array and Deerfield Private Design Fund, L.P. and Deerfield Private Design International, L.P., healthcare investment funds,  who we collectively refer to as the Deerfield Funds, we issued warrants to purchase 6,000,000 shares of our common stock to the Deerfield Funds and entered into a Registration Rights Agreement dated April 29, 2008 with the Deerfield Funds. Under the terms of the Registration Rights Agreement, we agreed to file a registration statement with the SEC on or prior to 30 days from the date the warrants were issued requiring us to register the resale of the shares of the common stock subject to issuance upon the exercise of the warrants under the Securities Act of 1933. On May 29, 2008, we filed a registration statement on Form S-3 registering the shares issuable upon exercise of the warrants, which the SEC declared effective as of June 10, 2008. We are generally required to bear all expenses of registration, including the reasonable fees of a single counsel acting on behalf of all selling stockholders, except underwriting discounts and selling commissions.

Registration of any shares with registration rights would result in those shares becoming freely tradeable without restriction under the Securities Act.  Sales of these shares, whether pursuant to Rule 144 under the Securities Act or a an effective registration statement, could have a material adverse effect on the trading price of our common stock.

Limitation of Liability of Directors and Officers

As permitted by the Delaware General Corporation Law, our amended and restated certificate of incorporation provides that our directors are not personally liable to us or our stockholders for monetary damages for breach of fiduciary duty as a director, except for liability:

·                  for any breach of the director’s duty of loyalty to us or our stockholders;

·                  for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law;

·                  under Section 174 of the Delaware General Corporation Law, relating to unlawful dividends or unlawful stock purchases or redemptions; or

·                  for any transaction from which the director derives an improper personal benefit.

As a result of this provision, we and our stockholders may be unable to obtain monetary damages from a director for breach of his or her duty of care.

Indemnification

Our bylaws provide for the indemnification of our directors and officers to the fullest extent authorized by the Delaware General Corporation Law.  We will indemnify a director or officer in connection with an action initiated by that person if the action was authorized by our board of directors.  The indemnification provided under our

6

Table of Contents

bylaws includes the right to be paid expenses in advance of the final disposition of a proceeding for which indemnification may be had if the director or officer agrees to repay all amounts paid in advance if it is ultimately determined that the director or officer is not entitled to be indemnified.  Under our bylaws, if we do not pay a claim for indemnification within 60 days after we have received a written claim, the director or officer may bring an action to recover the unpaid amount of the claim. If successful, the director or officer also will be entitled to be paid the expense of prosecuting the action to recover these unpaid amounts.

Our bylaws also authorize us to purchase and maintain insurance on behalf of any person who is or was one of our directors, officers, employees or agents, or is or was serving at our request as a director, officer, employee, partner or agent of another corporation or other entity or enterprise, against any liability asserted against the person or incurred by the person in any of these capacities, or arising out of the person’s fulfilling one of these capacities, and related expenses.  We may obtain this insurance whether or not we would have the power to indemnify the person against the claim under the provisions of the Delaware General Corporation Law. We have purchased director and officer liability insurance on behalf of our directors and officers.  The indemnification provisions under our amended and restated certificate of incorporation and bylaws are not exclusive of any other rights to indemnification under any bylaw, agreement, vote of stockholders or disinterested directors or otherwise.

Anti-Takeover Provisions

General

Our amended and restated certificate of incorporation and bylaws contain some provisions that are intended to enhance the likelihood of continuity and stability in the composition of our board of directors and in the policies formulated by our board of directors.  In addition, provisions of Delaware law may hinder or delay an attempted takeover of us other than through negotiation with our board of directors.  These provisions could have the effect of discouraging attempts to acquire us or remove incumbent management even if some or a majority of our stockholders believe this action is in their best interest, including attempts that might result in the stockholders receiving a premium over the market price for the shares of common stock they hold.

Classified Board

Our amended and restated certificate of incorporation provides for the division of our board of directors into three classes of directors serving staggered three-year terms.  Our amended and restated certificate of incorporation further provides that the approval of the holders of at least two-thirds of the shares entitled to vote is necessary for the alteration, amendment or repeal of sections of our amended and restated certificate of incorporation relating to the election and classification of our board of directors, limitation of director liability, indemnification and the vote requirements for these amendments to our amended and restated certificate of incorporation. These provisions may have the effect of deterring hostile takeovers or delaying changes in control or management.

Removal of Directors and Vacancies

Our amended and restated certificate of incorporation provides that directors may be removed only with cause upon the affirmative vote of holders representing two-thirds of our outstanding shares. In addition, vacancies and newly created directorships resulting from any increase in the size of the board of directors may be filled only by the affirmative vote of a majority of the directors then in office, even if they do not constitute a quorum, or by the sole remaining director. These provisions would prevent stockholders from removing incumbent directors without cause and filling the resulting vacancies with their own nominees.

Advance Notice Provisions for Stockholder Proposals and Stockholder Nominations of Directors

Our bylaws establish an advance notice procedure with regard to the nomination, other than by the board of directors, of candidates for election to the board of directors and with regard to matters to be brought before an annual meeting of our stockholders by a stockholder. The stockholder’s notice must contain specified information regarding the stockholder and its holdings, as well as about the director nominee and any business desired to be brought before the meeting. Although our bylaws do not give our board of directors any power to approve or

7

Table of Contents

disapprove stockholder nominations for the election of directors or any other business desired by stockholders to be conducted at an annual meeting, the bylaws:

·                  may have the effect of precluding a nomination for the election of directors or precluding the conduct of business at a particular annual meeting if the proper procedures are not followed; or

·                  may discourage or deter a third party from conducting a solicitation of proxies to elect its own slate of directors or otherwise attempting to obtain control of us, even if the conduct of this solicitation or the attempt to obtain control might be beneficial to us and our stockholders.

Special Stockholders’ Meetings

Under our amended and restated certificate of incorporation and bylaws, special meetings of stockholders, unless otherwise prescribed by statute, may be called only by the board of directors, the chairperson, or the chief executive officer.

Stockholder Action Without a Meeting Only by Unanimous Written Consent

Our amended and restated certificate of incorporation provides that any action required or permitted to be taken at a stockholders’ meeting may be taken without a meeting only by unanimous written consent.

Section 203 of the Delaware General Corporation Law

Under Section 203 of the Delaware General Corporation Law, we may not engage in a “business combination,” which includes a merger or sale of more than 10% of our assets, with any “interested stockholder,” namely, a stockholder who owns 15% or more of our outstanding voting stock, as well as affiliates and associates of any of these persons, for three years following the time that stockholder became an interested stockholder, unless:

·                  the transaction in which the stockholder became an interested stockholder is approved by our board of directors prior to the time the interested stockholder attained that status;

·                  upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85% of our voting stock outstanding at the time the transaction commenced, excluding those shares owned by persons who are directors and also officers; or

·                  at or after the time the stockholder became an interested stockholder the business combination is approved by the board of directors and authorized at an annual or special meeting of stockholders by the affirmative vote of at least two-thirds of the outstanding voting stock that is not owned by the interested stockholder.

Authorized but Unissued Shares

The authorization of undesignated preferred stock makes it possible for the board of directors to issue preferred stock with voting or other rights or preferences that could impede the success of any attempt to change control of our company. These and other provisions may have the effect of deterring hostile takeovers or delaying changes in control or management of our company.

Rights Plan

On August 2, 2001, our board of directors adopted a Rights Agreement, pursuant to which all stockholders of record as of August 27, 2001 received rights to purchase shares of a newly created series of preferred stock. Each right entitles the registered holder to purchase from us one-one hundredth of a share of Series A Junior Participating Preferred Stock at an exercise price of $70.00 per share, subject to adjustment. The rights will become exercisable 10 business days after announcement that a person or group has acquired or obtained the right to acquire 15% or more of our outstanding common stock or 10 business days after commencement or announcement of a tender or exchange offer for 15% or more of our outstanding common stock. If a person or group acquires 15% or more of our

8

Table of Contents

outstanding common stock, all rights holders, except the acquiring person or group, will be entitled to acquire our common stock at a discount. In the event that we are acquired in a merger or other business combination transaction in which we are not the surviving corporation, or 50% or more of our assets or earning power is sold or transferred to a person or group who has acquired 15% or more of our outstanding capital stock, proper provision will be made so that each such holder of a right will have the right to receive, upon exercise of the right, shares of common stock of the acquiring company which at the time of the transaction will have a market value of two times the exercise price of the right.

Our board of directors may terminate the rights plan at any time, amend the rights plan without the approval of any holders of the rights or redeem the rights within 10 business days of the date a person or group acquires 15% or more of our outstanding capital stock. The rights expire on August 2, 2011.

The form of Rights Agreement specifying the terms of the rights, which includes the form of Certificate of Designation of the Series A Junior Participating Preferred Stock, the Summary of Rights to Purchase Series A Junior Participating Preferred Stock and the form of Rights Certificate, is attached as an exhibit to the Registration Statement on Form 8-A filed by Array with the SEC on August 3, 2001. The foregoing description of the rights is only a summary and is qualified in its entirety by reference to the complete text of the Rights Agreement.

DESCRIPTION OF DEPOSITARY SHARES

We may offer fractional shares of preferred stock rather than full shares of preferred stock, and, in that event, will issue receipts for depositary shares. Each of these depositary shares will represent a fraction, which will be set forth in the applicable prospectus supplement, of a share of the applicable series of preferred stock.

The shares of any series of preferred stock underlying any depositary shares that we may sell under this prospectus will be deposited under a deposit agreement between us and a depositary selected by us. Subject to the terms of the deposit agreement, each holder of a depositary share will be entitled, in proportion to the applicable fraction of a share of the preferred stock underlying the depositary share, to all of the rights, preferences and privileges, and be subject to the qualifications and restrictions, of the preferred stock underlying that depositary share.

The depositary shares will be evidenced by depositary receipts issued under a deposit agreement. Depositary receipts will be distributed to the holders of the depositary shares that are sold in the applicable offering. We will incorporate by reference into the registration statement of which this prospectus is a part the form of any deposit agreement, including a form of depositary receipt, that describes the terms of any depositary shares we are offering before the issuance of the related depositary shares. The following summaries of material provisions of the deposit agreement, the depositary shares and the depositary receipts are subject to, and qualified in their entirety by reference to, all of the provisions of the deposit agreement applicable to a particular offering of depositary shares. We urge you to read the prospectus supplements relating to any depositary shares that are sold under this prospectus, as well as the complete deposit agreement and depositary receipt.

9

Table of Contents

Form

Pending the preparation of definitive depositary receipts, the depositary may, upon our written order, issue temporary depositary receipts substantially identical to the definitive depositary receipts but not in definitive form. These temporary depositary receipts entitle their holders to all of the rights of definitive depositary receipts. Temporary depositary receipts will then be exchangeable for definitive depositary receipts at our expense.

Dividends and Other Distributions

The depositary will distribute all cash dividends or other cash distributions received with respect to the underlying preferred stock to the record holders of depositary shares in proportion to the number of depositary shares owned by those holders.

If there is a distribution other than in cash, the depositary will distribute property received by it to the record holders of depositary shares in proportion to the number of depositary shares owned by those holders, unless the depositary determines that it is not feasible to do so. If this occurs, the depositary may, with our approval, sell the property and distribute the net proceeds from the sale to those holders in proportion to the number of depositary shares owned by them.

Withdrawal of Underlying Preferred Stock

Except as otherwise provided in a prospectus supplement, holders may surrender depositary receipts at the principal office of the depositary and, upon payment of any unpaid amount due to the depositary, be entitled to receive the number of whole shares of underlying preferred stock and all money and other property represented by the related depositary shares. We will not issue any partial shares of preferred stock. If the holder delivers depositary receipts evidencing a number of depositary shares that represent more than a whole number of shares of preferred stock, the depositary will issue a new depositary receipt evidencing the excess number of depositary shares to the holder.

Redemption of Depositary Shares

If the preferred stock underlying any depositary shares we may sell under this prospectus is subject to redemption, the depositary shares will be redeemed from the proceeds received by the depositary resulting from any such redemption, in whole or in part, of that underlying preferred stock. The redemption price per depositary share will be equal to the applicable fraction of the redemption price per share payable with respect to the underlying preferred stock. Whenever we redeem shares of underlying preferred stock that are held by the depositary, the depositary will redeem, as of the same redemption date, the number of depositary shares representing the shares of underlying preferred stock so redeemed. If fewer than all of the depositary shares are to be redeemed, the depositary shares to be redeemed will be selected by lot or proportionately, as may be determined by the depositary.

Voting

Upon receipt of notice of any meeting at which holders of the preferred stock underlying any depositary shares that we may sell under this prospectus are entitled to vote, the depositary will mail the information contained in the notice to the record holders of the depositary shares. Each record holder of the depositary shares on the record date, which will be the same date as the record date for the underlying preferred stock, will be entitled to instruct the depositary as to the exercise of the voting rights pertaining to the amount of the underlying preferred stock represented by the holder’s depositary shares. The depositary will then try, as far as practicable, to vote the number of shares of preferred stock underlying those depositary shares in accordance with those instructions, and we will agree to take all reasonable actions which may be deemed necessary by the depositary to enable the depositary to do so. The depositary will not vote the underlying preferred stock to the extent it does not receive specific instructions with respect to the depositary shares representing such preferred stock.

10

Table of Contents

Conversion of Preferred Stock

If the prospectus supplement relating to any depositary shares that we may sell under this prospectus states that the underlying preferred stock is convertible into our common stock or other securities, the following will apply. The depositary shares, as such, will not be convertible into any of our securities. Rather, any holder of the depositary shares may surrender the related depositary receipts to the depositary with written instructions that direct us to cause conversion of the preferred stock represented by the depositary shares into or for whole shares of our common stock or other securities, as applicable. Upon receipt of those instructions and any amounts payable by the holder in connection with the conversion, we will cause the conversion using the same procedures as those provided for conversion of the underlying preferred stock. If only some of a holder’s depositary shares are converted, a new depositary receipt or receipts will be issued to the holder for any depositary shares not converted.

Amendment and Termination of the Deposit Agreement

The form of depositary receipt evidencing the depositary shares and any provision of the deposit agreement may at any time be amended by agreement between us and the depositary. However, any amendment which materially and adversely alters the rights of the holders of depositary shares will not be effective until 90 days after notice of that amendment has been given to the holders. Each holder of depositary shares at the time any amendment becomes effective shall be deemed to consent and agree to that amendment and to be bound by the deposit agreement as so amended. The deposit agreement may be terminated by us or by the depositary only if all outstanding depositary shares have been redeemed or converted into any other securities into which the underlying preferred stock is convertible or there has been a final distribution, including to holders of depositary receipts, of the underlying preferred stock in connection with our liquidation, dissolution or winding up.

Charges of Depositary

We will pay all charges of the depositary, except for taxes and governmental charges and other charges as are expressly provided for in the deposit agreement to be for the account of the holders of depositary shares or persons other than ourselves who may deposit any underlying preferred stock with the depositary.

Reports

The depositary will forward to holders of depositary receipts all notices and reports from us that we deliver to the depositary and that we are required to furnish to the holders of the underlying preferred stock.

Limitation on Liability

Neither we nor the depositary will be liable if either of us is prevented or delayed by law or any circumstance beyond our control in performing our respective obligations under the deposit agreement. Our obligations and those of the depositary will be limited to performance of our respective duties under the deposit agreement without, in our case, negligence or bad faith or, in the case of the depositary, negligence or willful misconduct. We and the depositary may rely upon advice of counsel or accountants, or upon information provided by persons presenting the underlying preferred stock for deposit, holders of depositary receipts or other persons believed by us in good faith to be competent and on documents believed to be genuine.

Resignation and Removal of Depositary

The depositary may resign at any time by delivering notice to us of its election to resign. We may remove the depositary at any time. Any resignation or removal will take effect upon the appointment of a successor depositary and its acceptance of the appointment. The successor depositary must be appointed within 60 days after delivery of the notice of resignation or removal and must be a bank or trust company having its principal office in the United States and having a combined capital and surplus of at least $50,000,000.

11

Table of Contents

DESCRIPTION OF WARRANTS

General

The following description, together with the additional information we may include in any applicable prospectus supplements, summarizes the material terms and provisions of the warrants that we may offer under this prospectus and the related warrant agreements and warrant certificates. While the terms summarized below will apply generally to any warrants we may offer, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. The form for each type of warrant will be filed as an exhibit to the registration statement of which this prospectus is a part.

We may issue, together with other securities or separately, warrants to purchase preferred stock or common stock. We will issue the warrants under warrant agreements to be entered into between us and a bank or trust company, as warrant agent, all as shall be set forth in the applicable prospectus supplement. The warrant agent will act solely as our agent in connection with the warrants of the series being offered and will not assume any obligation or relationship of agency or trust for or with any holders or beneficial owners of warrants.

Further terms of the warrants will be set forth in the applicable prospectus supplement, including, where applicable, the following:

·                  the title of such warrants;

·                  the aggregate number of warrants;

·                  the price or prices at which the warrants will be issued;

·                  the designation, terms and number of shares of common stock, preferred stock or depositary shares purchasable upon exercise of the warrants;

·                  the designation and terms of the securities with which the warrants are issued and the number of warrants issued with such securities;

·                  the date on and after which the warrants and the related securities will be separately transferable, including any limitations on ownership and transfer of the warrants;

·                  in the case of warrants to purchase common stock, preferred stock or depositary shares, the price at which each share of common stock, preferred stock or depositary share purchasable upon exercise of the warrants may be purchased;

·                  any provisions for adjustment of the number or amount of securities receivable upon exercise of the warrants;

·                  the dates on which the right to exercise the warrants shall commence and expire;

·                  the minimum or maximum amount of warrants that may be exercised at any one time;

·                  information with respect to book-entry procedures, if any;

·                  a discussion of certain federal income tax consequences; and

·                  any other terms of the warrants, including terms, procedures and limitations relating to the exchange and exercise of the warrants.

12

Table of Contents

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including in the case of warrants to purchase common stock, preferred stock or depositary shares, the right to receive dividends, if any, or payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any.

Exercise of Warrants

Each warrant will entitle the holder thereof to purchase for cash the securities at the exercise price as shall in each case be set forth in, or be determinable as set forth in, the applicable prospectus supplement.  Warrants may be exercised at any time up to the close of business on the expiration date set forth in the applicable prospectus supplement.  After the close of business on the expiration date, unexercised warrants will become void.

Holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement.  We will set forth on the reverse side of the warrant certificate and in the applicable prospectus supplement the information that the holder of the warrant will be required to deliver to the warrant agent.

Warrants may be exercised as set forth in the applicable prospectus supplement relating to the warrants offered thereby.  Upon receipt of payment of the exercise price and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will, as soon as practicable, forward the purchased securities.  If less than all of the warrants represented by the warrant certificate are exercised, a new warrant certificate will be issued for the remaining warrants.  If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

13

Table of Contents

Enforceability of Rights of Holders of Warrants

Each warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant.  A single bank or trust company may act as a warrant agent for more than one issue of warrants.  A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us.  Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, that holder’s warrants.

Outstanding Warrants

As of November 5, 2008, there were outstanding warrants to purchase 6,000,000 shares of our common stock at an exercise price of $7.54 per share.  The warrants expire April 29, 2016, unless earlier exercised.  The warrants are not exercisable to the extent such exercise would cause the holder thereof to beneficially own more than 9.98% of our outstanding capital stock.  Such warrants were filed as an exhibit to our current report on Form 8-K filed with the SEC on May 5, 2008 (file no. 001-16633).

LEGAL OWNERSHIP OF SECURITIES

We can issue securities in registered form or in the form of one or more global securities. We describe global securities in greater detail below.  We refer to those persons who have securities registered in their own names on the books that we or any applicable trustee, depositary or warrant agent maintain for this purpose as the “holders” of those securities.  These persons are the legal holders of the securities.  We refer to those persons who, indirectly through others, own beneficial interests in securities that are not registered in their own names, as “indirect holders” of those securities. As we discuss below, indirect holders are not legal holders, and investors in securities issued in book-entry form or in street name will be indirect holders.

Book-Entry Holders

We may issue securities in book-entry form only, as we will specify in the applicable prospectus supplement. This means securities may be represented by one or more global securities registered in the name of a financial institution that holds them as depositary on behalf of other financial institutions that participate in the depositary’s book-entry system. These participating institutions, which are referred to as participants, in turn, hold beneficial interests in the securities on behalf of themselves or their customers.

Only the person in whose name a security is registered is recognized as the holder of that security. Securities issued in global form will be registered in the name of the depositary or its participants.  Consequently, for securities issued in global form, we will recognize only the depositary as the holder of the securities, and we will make all payments on the securities to the depositary.  The depositary passes along the payments it receives to its participants, which in turn pass the payments along to their customers who are the beneficial owners. The depositary and its participants do so under agreements they have made with one another or with their customers; they are not obligated to do so under the terms of the securities.

As a result, investors in a book-entry security will not own securities directly.  Instead, they will own beneficial interests in a global security, through a bank, broker or other financial institution that participates in the depositary’s book-entry system or holds an interest through a participant.  As long as the securities are issued in global form, investors will be indirect holders, and not holders, of the securities.

14

Table of Contents

Street Name Holders

We may terminate a global security or issue securities in non-global form. In these cases, investors may choose to hold their securities in their own names or in “street name.”  Securities held by an investor in street name would be registered in the name of a bank, broker or other financial institution that the investor chooses, and the investor would hold only a beneficial interest in those securities through an account he or she maintains at that institution.

For securities held in street name, we will recognize only the intermediary banks, brokers and other financial institutions in whose names the securities are registered as the holders of those securities, and we will make all payments on those securities to them.  These institutions pass along the payments they receive to their customers who are the beneficial owners, but only because they agree to do so in their customer agreements or because they are legally required to do so. Investors who hold securities in street name will be indirect holders, not holders, of those securities.

Legal Holders

Our obligations, as well as the obligations of any applicable trustee and of any third parties employed by us or a trustee, run only to the legal holders of the securities.  We do not have obligations to investors who hold beneficial interests in global securities, in street name or by any other indirect means.  This will be the case whether an investor chooses to be an indirect holder of a security or has no choice because we are issuing the securities only in global form.

For example, once we make a payment or give a notice to the holder, we have no further responsibility for the payment or notice even if that holder is required, under agreements with depositary participants or customers or by law, to pass it along to the indirect holders but does not do so. Similarly, we may want to obtain the approval of the holders to amend an indenture, to relieve us of the consequences of a default or of our obligation to comply with a particular provision of the indenture or for other purposes. In such an event, we would seek approval only from the holders, and not the indirect holders, of the securities. Whether and how the holders contact the indirect holders is up to the holders.

Special Considerations For Indirect Holders

If you hold securities through a bank, broker or other financial institution, either in book-entry form or in street name, you should check with your own institution to find out:

·                  how it handles securities payments and notices;

·                  whether it imposes fees or charges;

·                  how it would handle a request for the holders’ consent, if ever required;

·                  whether and how you can instruct it to send you securities registered in your own name so you can be a holder, if that is permitted in the future;

·                  how it would exercise rights under the securities if there were a default or other event triggering the need for holders to act to protect their interests; and

·                  if the securities are in book-entry form, how the depositary’s rules and procedures will affect these matters.

15

Table of Contents

Global Securities

A global security is a security that represents one or any other number of individual securities held by a depositary.  Generally, all securities represented by the same global securities will have the same terms.

Each security issued in book-entry form will be represented by a global security that we deposit with and register in the name of a financial institution or its nominee that we select.  The financial institution that we select for this purpose is called the depositary.  Unless we specify otherwise in the applicable prospectus supplement, The Depositary Trust Company, New York, New York, known as DTC, will be the depositary for all securities issued in book-entry form.

A global security may not be transferred to or registered in the name of anyone other than the depositary, its nominee or a successor depositary, unless special termination situations arise.  We describe those situations below under “Special Situations When a Global Security Will Be Terminated.”  As a result of these arrangements, the depositary, or its nominee, will be the sole registered owner and holder of all securities represented by a global security, and investors will be permitted to own only beneficial interests in a global security. Beneficial interests must be held by means of an account with a broker, bank or other financial institution that in turn has an account with the depositary or with another institution that does.  Thus, an investor whose security is represented by a global security will not be a holder of the security, but only an indirect holder of a beneficial interest in the global security.

If the prospectus supplement for a particular security indicates that the security will be issued in global form only, then the security will be represented by a global security at all times unless and until the global security is terminated. If termination occurs, we may issue the securities through another book-entry clearing system or decide that the securities may no longer be held through any book-entry clearing system.

Special Considerations For Global Securities

As an indirect holder, an investor’s rights relating to a global security will be governed by the account rules of the investor’s financial institution and of the depositary, as well as general laws relating to securities transfers. We do not recognize an indirect holder as a holder of securities and instead deal only with the depositary that holds the global security.

If securities are issued only in the form of a global security, an investor should be aware of the following:

·                  An investor cannot cause the securities to be registered in his or her name, and cannot obtain non-global certificates for his or her interest in the securities, except in the special situations we describe below;

·                  An investor will be an indirect holder and must look to his or her own bank or broker for payments on the securities and protection of his or her legal rights relating to the securities, as we describe above;

·                  An investor may not be able to sell interests in the securities to some insurance companies and to other institutions that are required by law to own their securities in non-book-entry form;

·                  An investor may not be able to pledge his or her interest in a global security in circumstances where certificates representing the securities must be delivered to the lender or other beneficiary of the pledge in order for the pledge to be effective;

·                  The depositary’s policies, which may change from time to time, will govern payments, transfers, exchanges and other matters relating to an investor’s interest in a global security.  We and any applicable trustee have no responsibility for any aspect of the depositary’s actions or for its records of ownership interests in a global security. We and the trustee also do not supervise the depositary in any way;

·                  The depositary may, and we understand that DTC will, require that those who purchase and sell interests in a global security within its book-entry system use immediately available funds, and your broker or bank may require you to do so as well; and

16

Table of Contents

·                  Financial institutions that participate in the depositary’s book-entry system, and through which an investor holds its interest in a global security, may also have their own policies affecting payments, notices and other matters relating to the securities. There may be more than one financial intermediary in the chain of ownership for an investor. We do not monitor and are not responsible for the actions of any of those intermediaries.

Special Situations When A Global Security Will Be Terminated

In a few special situations described below, the global security will terminate and interests in it will be exchanged for physical certificates representing those interests.  After that exchange, the choice of whether to hold securities directly or in street name will be up to the investor.  Investors must consult their own banks or brokers to find out how to have their interests in securities transferred to their own name, so that they will be direct holders. We have described the rights of holders and street name investors above.

The global security will terminate when the following special situations occur:

·                  if the depositary notifies us that it is unwilling, unable or no longer qualified to continue as depositary for that global security and we do not appoint another institution to act as depositary within 90 days;

·                  if we notify any applicable trustee that we wish to terminate that global security; or

·                  if an event of default has occurred with regard to securities represented by that global security and has not been cured or waived.

The prospectus supplement may also list additional situations for terminating a global security that would apply only to the particular series of securities covered by the prospectus supplement.  When a global security terminates, the depositary, and not we or any applicable trustee, is responsible for deciding the names of the institutions that will be the initial direct holders.

PLAN OF DISTRIBUTION

We may sell the securities being offered by this prospectus separately or together through any of the following methods:

·                  directly to purchasers;

·                  through agents;

·                  to or through one or more underwriters or dealers;

·                  through a block trade in which the broker or dealer engaged to handle the block trade will attempt to sell the securities as agent, but may position and resell a portion of the block as principal to facilitate the transaction; and

·                  through a combination of any of these methods of sale.

We may effect the distribution of the securities from time to time in one or more transactions:

·                  at a fixed price or prices, which may be changed from time to time;

·                  at market prices prevailing at the times of sale;

·                  at prices related to such prevailing market prices; or

17

Table of Contents

·                  at negotiated prices.

Each time we offer a type or series of securities, we will provide a prospectus supplement that will describe the specific amounts, prices and other important terms of the securities, as described above under “SUMMARY — Securities We May Offer.”

Agents.  We may solicit offers to purchase the securities offered by this prospectus through agents we designate from time to time. We will name any agent involved in the offer or sale of the securities and set forth any commissions payable by us to an agent in the applicable prospectus supplement. Unless otherwise indicated in the prospectus supplement, any agent will be acting on a best efforts basis for the period of his or her appointment. Any agent may be deemed to be an “underwriter” of the securities as that term is defined in the Securities Act of 1933 (the “Securities Act”).

Underwriters.  If we use an underwriter or underwriters in the sale of securities, we will execute an underwriting agreement with the underwriter or underwriters at the time we reach an agreement for sale. The underwriter or underwriters will acquire the securities for their own account and may resell the securities from time to time in one or more transactions at a fixed public offering price or at varying prices determined at the time of sale. The obligations of an underwriter or underwriters to purchase the securities will be subject to the conditions set forth in the applicable underwriting agreement. We will set forth in the prospectus supplement the names of the specific managing underwriter or underwriters, as well as any other underwriters, and the terms of the transactions, including compensation of the underwriters and dealers. This compensation may be in the form of discounts, concessions or commissions. We may use underwriters with whom we have a material relationship.  Underwriters and others participating in any offering of the securities may engage in transactions that stabilize, maintain or otherwise affect the price of the securities. We will describe any such relationship and any of these activities in the prospectus supplement.

Dealers.  If a dealer is used in the sale of the securities, an underwriter or we will sell securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale. The prospectus supplement will set forth the name of the dealer and the terms of the transactions.

Direct Sales.  We may directly solicit offers to purchase the securities, and we may sell directly to institutional investors or others. These persons may be deemed to be underwriters within the meaning of the Securities Act with respect to any resale of the securities. The prospectus supplement will describe the terms of any direct sales, including the terms of any bidding or auction process.

Indemnification.  Agreements we enter into with agents, underwriters and dealers may entitle them to indemnification by us against specified liabilities, including liabilities under the Securities Act, or to contribution by us to payments they may be required to make in respect of these liabilities. The prospectus supplement will describe the terms and conditions of indemnification or contribution.

Delayed Delivery Contracts.  We may authorize underwriters, dealers and agents to solicit offers by certain institutional investors to purchase offered securities under contracts providing for payment and delivery on a future date specified in the prospectus supplement. The prospectus supplement will also describe the public offering price for the securities and the commission payable for solicitation of these delayed delivery contracts. Delayed delivery contracts will contain definite fixed price and quantity terms. The obligations of a purchaser under these delayed delivery contracts will be subject to only two conditions:

·                  that the institution’s purchase of the securities at the time of delivery of the securities is not prohibited under the law of any jurisdiction to which the institution is subject; and

·                  that we shall have sold to the underwriters the total principal amount of the offered securities, less the principal amount covered by the delayed delivery contracts.

Stabilization Activities.  To the extent permitted by and in accordance with Regulation M under the Securities Exchange Act of 1934 (the “Exchange Act”), in connection with an offering an underwriter may engage in over-

18

Table of Contents

allotments, stabilizing transactions, short covering transactions and penalty bids. Over-allotments involve sales in excess of the offering size, which creates a short position. Stabilizing transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum. Short covering transactions involve purchases of the securities in the open market after the distribution is completed to cover short positions. Penalty bids permit the underwriters to reclaim a selling concession from a dealer when the securities originally sold by the dealer are purchased in a covering transaction to cover short positions. Those activities may cause the price of the securities to be higher than it would be otherwise. If commenced, the underwriters may discontinue any of these activities at any time.

Passive Market Making.  To the extent permitted by and in accordance with Regulation M under the Exchange Act, any underwriters who are qualified market makers on the Nasdaq Global Market may engage in passive market making transactions in the securities on the Nasdaq Global Market during the business day prior to the pricing of an offering, before the commencement of offers or sales of the securities. Passive market makers must comply with applicable volume and price limitations and must be identified as passive market makers. In general, a passive market maker must display its bid at a price not in excess of the highest independent bid for such security; if all independent bids are lowered below the passive market maker’s bid, however, the passive market maker’s bid must then be lowered when certain purchase limits are exceeded.

Trading Markets and Listing. Unless otherwise specified in the applicable prospectus supplement, each class or series of securities will be a new issue with no established trading market, other than our common stock, which is listed on the Nasdaq Global Market. We may elect to list any other class or series of securities on any exchange, but we are not obligated to do so. It is possible that one or more underwriters may make a market in a class or series of securities, but the underwriters will not be obligated to do so and may discontinue any market making at any time. We cannot give any assurance as to the liquidity of the trading market for any of the securities we may offer under this prospectus.

No securities may be sold under this prospectus without delivery, in paper format, in electronic format on the Internet, or both, of the applicable prospectus supplement describing the method and terms of the offering.

LEGAL MATTERS

Hogan & Hartson L.L.P., Boulder, Colorado, will provide us with an opinion as to certain legal matters in connection with the issuance and sale of the securities.

EXPERTS

The financial statements of Array BioPharma Inc. as of June 30, 2008 and 2007, and for each of the years in the three-year period ended June 30, 2008, have been incorporated by reference herein and in the registration statement in reliance upon the reports of KPMG LLP, independent registered public accounting firm, and upon the authority of said firm as experts in accounting and auditing.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to incorporate by reference the information that we file with the SEC, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is considered to be part of this prospectus. These documents may include periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, as well as Proxy Statements. Any documents that we subsequently file with the SEC will automatically update and replace the information previously filed with the SEC. Thus, for example, in the case of a conflict or inconsistency between information set forth in this prospectus and information incorporated by reference into this prospectus, you should rely on the information contained in the document that was filed later.

This prospectus incorporates by reference the documents listed below that we have previously filed with the SEC (under File No. 001-16633) and any additional documents that we may file with the SEC under Sections 13(a),

19

Table of Contents

13(c), 14 or 15(d) of the Exchange Act between the date of this prospectus and the termination of the offering of the securities. These documents contain important information about us.

1.               Our Annual Report on Form 10-K for the year ended June 30, 2008 filed with the SEC on August 15, 2008;

2.     Our Definitive Proxy Statement on Schedule 14A for our annual meeting of stockholders, filed with the SEC on September 23, 2008;

3                  Our Quarterly Report on Form 10-Q filed with the SEC on November 4, 2008 for the quarter ended September 30, 2008;

4.     Our Current Reports on Form 8-K filed with the SEC on July 31, 2008, September 8, 2008, September 19, 2008, September 25, 2008, October 29, 2008 and November 4, 2008 (except to the extent such information was furnished to and not filed with the SEC); and

5.     The description of our common stock contained in our Registration Statement on Form 8-A filed with the SEC on November 16, 2000, and the description of our preferred stock purchase rights contained in our Registration Statement on Form 8-A filed with the SEC on August 3, 2001, including any amendment or report filed for the purpose of updating such descriptions.

You can obtain a copy of any or all of these documents, including any exhibits thereto, at no cost, by visiting the Investor Relations section of our web site at http://www.arraybiopharma.com or by requesting them in writing or by telephone at the following address:

Array BioPharma Inc.
3200 Walnut Street
Boulder, Colorado 80301
(303) 381-6600
Attention: Investor Relations

See also the section entitled “Where You Can Find More Information” below.

Statements contained in this prospectus and the documents incorporated by reference herein referring to the contents of any contract or other document are not necessarily complete.  Where such contract or other document is listed as an exhibit to the Registration Statement on Form S-3, of which this prospectus forms a part, or any document incorporated by reference therein, each such statement is qualified by the provisions in such exhibit, to which reference is hereby made.

Information contained on our website does not constitute a part of this prospectus.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement under the Securities Act that registers the distribution of the securities offered under this prospectus. The registration statement, including the attached exhibits and schedules and the information incorporated by reference, contains important information about our company and the securities. The rules and regulations of the SEC allow us to omit from this prospectus certain information included in the registration statement. In addition, we file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy this information and the registration statement at the SEC’s Public Reference Room located at 100 F Street, N.E., Washington D.C. 20549. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the public reference room.

In addition, any information we file with the SEC, including the registration statement and the documents incorporated by reference into this prospectus, and the exhibits thereto, is also available on the SEC’s website at http://www.sec.gov. We also maintain a web site at http://www.arraybiopharma.com, which provides additional

20

Table of Contents

information about our company and through which you can also access our SEC filings. The information set forth on our web site is not part of this prospectus.

DISCLOSURE OF COMMISSION POSITION ON INDEMNIFICATION FOR

SECURITIES ACT LIABILITIES

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable.

21

Table of Contents

$25,000,000

ARRAY BIOPHARMA INC.

Common Stock

PROSPECTUS SUPPLEMENT

Piper Jaffray

September 18, 2009